An air conditioning system typically includes a condenser, an evaporator, a pump and fluid circuit interconnecting these elements. The evaporator generally has a heat exchanger with a number of core units and a header which receives refrigerant from the fluid circuit and distributes refrigerant to each of the core units. The refrigerant is then returned to the fluid circuit.
Headers often include a plurality of conduits or tubes branching off of an inlet from the fluid circuit and connecting to openings in the core units. These headers attempt to distribute an even flow of refrigerant to the core units. The ends of the conduits are conventionally brazed in a hand assembly operation to the inlet and to each of the core units.
A number of problems are associated with the use of such headers. First, manufacture of these headers is labor intensive and is not well suited to automated manufacture. Each of the conduits must be individually brazed to the inlet and to the openings in each of the core units. This brazing is generally manually performed due to the awkward stalk-like configuration of the branching conduits.
Another problem results from the difficulty of distributing low pressure fluids. Because the length of the conduits between the inlet and the core units can vary, refrigerant passing through the header seeks the path of least resistance which is usually the shortest conduit. Accordingly, the quantities of refrigerant reaching each of the core units is not uniform thereby reducing the efficiency of the heat exchanger.
Also, this type of header is not particularly compact. Often numerous conduits are required to reach the appropriate openings in the core units. Therefore, packaging of the header in an evaporator unit can be difficult.
The present invention provides an improved header, evaporator and methods of making the same which solve some of the aforementioned problems.